How to measure and reframe sedentary behaviour and physical activity

What are the best measures to take when measuring sedentary behaviour and physical activity measurement? Do we have a fundamental problem in our approach to measuring sedentary behaviour and physical activity? Is this negatively impacting our attempts to understand these behaviours and find effective interventions?

If the measure at the top of your pyramid is only best at assessing energy expenditure, then your hierarchy is for energy expenditure, not physical activity or sedentary behaviour; it tells you nothing about the usual pace of walking, or workplace screen-time for example, which are both potentially important determinants of health.

So, we argue that the question we should ask is ‘What is my research aim?’ and ‘Which measure best addresses my aim?’ not ‘Which measure is closest to the top of the hierarchy?’ Unless your aim is to assess energy expenditure or some closely related concept, the prevailing hierarchy may be leading you astray.

Sedentary behaviour and physical activity are not single, simple things

We all know this; physical activity is a broad set of behaviours including gentle walks, perhaps with friends or your dogs, cycling to work, weekend sports, training for a 5k, gardening, housework and for some occupational activity. Similarly, sedentary behaviour may be sitting in a café with a friend, staring at a computer screen at our desks at work (as the writer currently is!), lying on a bed reading or studying, or reclining on the sofa enjoying our favourite TV show (or some terrible mind numbing show – insert your own option).

Each of these behaviours may have different impacts on physical, mental and social health and require different approaches to promote or reduce them. What we often forget is that they are likely to need different approaches to measure them as well. How well a measure agrees with a certain gold standard is only relevant if that gold standard measures the behavioural construct of interest.

For example, let’s say we wanted to assess the way people commute to work (e.g. car, bus, walk or cycle). Self-report of mode and usual distance is likely to outperform a device based measure of movement or energy expenditure over a 7-day wear-time period. Conversely, if we want to know when in a 24 hour period most activity or sedentary time is accumulated a continuous device-based assessment will likely out-perform memory or recall.

Start with face and content validity in the context of your research aim

When it comes to selecting a measure, we recommend starting with face and content validity. In essence, this means; will the measure assess the construct (thing) of interest and how much of that thing will it cover? If you want to know about walking, laptop use, sport or other, use that to start the decision-making process (factoring in relevant considerations around ethics, feasibility and cost). If you are running an intervention, build a logic model; this will often tell you what you should be measuring and it will rarely be total energy expenditure!

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Hi, I'm Ryan, one of the bloggers here at Human Kinetics Europe Ltd. (If you want my official title, it's Marketing Executive.) I've always had a passion for health and fitness, having previously worked in gyms and played a variety of sports all my life. Now (as a somewhat of a washed-up athlete) I find myself working at the world’s biggest independent publisher of sport, health, dance and fitness resources. Which is amazing! Why? Because I get unrestricted access to all the best, most interesting, scientifically-proven writing on sports science. And what's more, I get to share it all with you!